Breathing apparatus



April 13, 1937. J B. pm

BREATHING APPARATUS Filed May 14, 1936 R. m .N w m M (f); WXb Lxmg JLLe/If fig ATTORNEYJ'L Patented Apr. 13, 1937 UNHTED STATES PATENT orrica BREATHING APPARATUS Application May 14,

Claims.

This invention relates to breathing apparatus of the type which includes a face-piece, or mask, that covers the entire face of the wearer, and more particularly'it relates to the prevention of fog- 5 ging of the eyepieces of such apparatus.

A serious problem that has confronted the art in the use of such breathing apparatus is due to the fogging of the eyepiece or lenses, with which the face-piece is provided, through condensation on the eyepiece of moisture in the air in the facepiece. Such condensate can not be wiped off the inside of the eyepiece without removing the mask, and since fogged lenses obscure the vision of the wearer this occurrence makes it dangerous, as well as difiicult, for the wearer to move about, as will be easily understood.

It is an object of this invention to provide breathing apparatus in which fogging of the inner surfaces of the face-piece lenses is minimized or eliminated.

The preferred embodiment of the invention is illustrated in the accompanying drawing in which Fig. 1 is a front view of a breathingmask incorporating the features of this invention; and

Fig. 2 a side view thereof, partly broken away to show the exhalation valve in vertical section.

Referring to the drawing, a face-piece l of rubber or other suitable flexible and gas-impervious material is provided in its upper portion with eyepieces or lenses 2, and at the sides of its forwardly projecting lower portion with tubular fittings 3 to which are connected flexible air hoses (not shown) which are also connected to the usual air-purifying canister, or to regenerating means where the mask is used with self-contained breathing apparatus. Although two fittings have been shown, it will be understood that a single fitting and a single hose may be used if desired.

Preferably, the lower front portion of the facepiece has an inwardly projecting portion 4 provided with a tubular opening 6 therethrough disposed to lie in front of the mouth of the wearer. The wall of this opening ,at its opposite ends flares outwardly like the bell .of a horn or a telephone transmitter, while its intermediate portion is provided with an annular recess l in which a speaking diaphragm is mounted. The diaphragm is preferably a thin metal plate 8 provided with concentric annular corrugations for increasing its flexibility and sensitivity, and it is clamped between a pair of clamping rings ll disposed in recess 1 where they are sealed, securely in place by binding the surrounding wall of the recess with wire i2 or the like.

1936, Serial No. 79,698

' The wearer of this mask speaks directly into the flared transmitter-like mouthpiece, and the metal diaphragm transmits his speech clearly to the outside of the face-piece with the aid of the megaphone effect produced by the flared portion of the face-piece outside the diaphragm. It will be noted that there is nothing to interfere with the speaking diaphragm or its operation, as has often been the case heretofore. The inwardly projecting portion of the face-piece serves likewise as a shock absorber in case the wearer is struck in the face, and prevents the metal diaphragm from hitting his lips and teeth.

To permit exhaled air to quickly and freely escape from the face-piece, the latter is provided with an exhalation valve 13, most suitably of the flutter type, as is the usual practice. However, it is a feature of this invention that the exhalation valve is located in such a positionthat the warm exhaled air passing therethrough is directed across the outer surfaces of the eyepiece lenses.

' .The resultant flow of exhaled air over the lenses tends to maintain their outer surfaces at a temperature substantially equal to that of the air inside the face-piece. As a result, the'condensa tion of moisture on the inner surfaces of the lenses is substantially prevented.

Accordingly, the exhalation valve is preferably of the flutter type, such as shown in Patent No. 1,515,645 to Yablick, and is mounted above inwardly projecting portion 4 of the face-piece in front of the nose of the wearer. The valve consists of two superimposed strips l4 and it of pliable rubber united at their edges except along their upper'side edges ll which are disposed substantially at right angles to each other (Fig. 1)

and form outlets for the valves. As shown in Fig.

2, inner strip [4 has an opening therethrough in which is disposed a tubular coupling It! the valve end of which is provided with an annular flange is projecting between the two sections of the valve. The other end of coupling l8 projects through an opening in the wall of the face-piece directly above its inwardly projecting portion 4, and the valve is clampedtightly against the face-piece by means of a nut 2i threaded on the inner end of the coupling.

With this construction, every time the wearer of the mask exhales, his breath enters the exhala tion valve through coupling l8, spreads'the two resilient sections of the valve apart and escapes in diverging paths from the unconnected upper edges ll of the valve by which it is directed across the outer surfaces of the lenses as indicated by the arrows in Fig. 1. The warm air striking the lensesin this manner keeps them .warm enough to substantially prevent condensation of moisture on their inner surfaces.

If desired, fogging of the lenses can be further 5 insured against by preventing as far as possible the exhaled air from-coming in contact with the inner surfaces of the lenses. This can be done by dividing the face-piece into two compartments sealed from each other, one containing the lenses and the other the air inlets and exhalation valve. Advantageously, this is accomplished by means of an inwardly projecting pliable rib 23, preferably molded into the face-piece, for snugly engaging the face of the wearer underneath his eyes and over the bridge of his nose.

However, ithas been found that the provision of separate eye and mouth compartments does not always prevent fogging because the air in the eye compartment'takes up moisture given ofi by the skin, and this moisture may condense on the lenses. Therefore, to remove moisture from the air in the eye compartment, a tube 24 is connected between each fitting 3 and the eye compartment, preferably directly below the overlying lens. The act of inhalation creates a partial vacuum in tubes 24 whereby some of the moist air in the eye compartment is drawn into the breathing compartment through the tubes 24 and the fittings along with the dry air from the air-purifying means (not shown).

To prevent exhalation through the air hoses, and particularly to prevent moist breath from entering the eye compartment through the tubes when the wearer exhales, check valves are provided that are preferably in the form of fiexible rubber discs 26 slidably mounted on headed pins 21 projecting inwardly from cross-pieces 28 mounted in fittings 3, as shown on Fig. 1. These valves make it unnecessary to have check valves in the canister to prevent exhaled air from passing through the canister on which such air has a detrimental efiect. When exhalation commences, the check valves close and the reduced pressure in the eye compartment (created during inhalation) causes dry air from the canister to enter the eye compartment. This incoming dry air further reduces the remaining moisture content of the air in the compartment.

Breathing apparatus constructed in accordance with this invention is safe and satisfactory in use because the vision of the wearer is not obstructed by fogged lenses, and the speech of the wearer can be distinctly understood through the mask without undue effort on his part. 7

According to the provisions of the patent statutes, I have explained the construction and operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. Breathing apparatus comprising a face-piece provided with an air inlet, an eyepiece mounted in said faceiece, and an exhalation valve mounted on the face-piece and positioned to direct the air exhaled therethrough across the outer surface or said eyepiece.

2; Breathing apparatus comprising a face-piece provided with an air inlet, a pair of lenses mounted in said face-piece, and an exhalation valve mounted on the face-piece between said lenses, said valve having outlet openings from which exhaled air passing through the valve is directed across the outer surfaces of said lenses.

3 Breathing apparatus comprising a face-piece provided with an air inlet, a pair of lenses mounted in said face-piece, and an exhalation valve mounted on the face-piece between and below said lenses, said valve being formed from two superimposed strips of resilient material secured together at their edge except at points adjacent said lenses, the inner of said strips being provided with an opening communicating with the interior of said face-piece, wherebyair exhaled through the valve passes across the outer surfaces of said lenses.

4. Breathing apparatus comprising a face-pieceprovided with an airinlet, an air-hose fitting associated with said inlet, an eyepiece mounted in said face-piece, means associated with" the inner surface of the face-piece and adapted to engage the face of a wearer for dividing the facepiece into eye and breathing compartments sealed from each other, a tube connecting said fitting to said eye compartment, a checkvalve mounted in the fitting between said tube and breathing compartment, and an exhalation valve connected to said breathing compartment, said exhalation valve being provided with an outlet adjacent said eyepiece for directing air exhaled therethrough across the outer surface of said eyepiece.

-5 Breathing apparatus comprising a face-piece provided with an air inlet, a pair "of lenses mounted in said face-piece, an exhalation valve mbunted on the face-piece between said lenses, said valve having outlet openings from which exhaled air passing through the valve is directed across the outer surfaces of said lenses, and a. speaking diaphragm 'mounted in the face-piece below said valve.

JOSEPH B.DYM. 

